Geoffroy’s bat forms colonies from May to August and changes roost sites frequently during this time. This species may live in large colonies (1); maternity colonies typically contain 20 to 200 individuals, but colonies comprising up to 1,000 females have been recorded (2). Male Geoffroy’s bats roost separately during this time. Geoffroy’s batmates in autumn, possibly also in winter, with females giving birth to a single young in June or July (2). Females may mate at one year of age and the maximum recorded lifespan of this species is 18 years (2).
Geoffroy’s bat feeds on flies, spiders, moths and other insects. It typically plucks its prey off surfaces, such as leaves, but may also capture insects during flight, generally within five metres of the ground. A study from central Europe found the most commonly occurring prey of this species were flies of the genus Musca, which are strongly associated with cattle farming (6). Geoffroy’s bat hunts at night, leaving the roost almost immediately after sunset and returning approximately one hour before sunrise, after travelling up to ten kilometres (7).